Vacuum cleaner and exhaust housing

ABSTRACT

A vacuum cleaner of the canister variety for domestic use having upper and lower housing sandwiching an intermediate housing therebetween. An air inlet is formed at the front of the upper housing and an exhaust housing is secured to the rear of the lower housing. A dust bag is positioned between the upper and intermediate housing and is separated from a motor blower assembly by an apertured partition wall. A washable permanent secondary filter, fitted about a wire form frame, is positioned on the dust bag side of the aperture in the partition wall by means of a pair of slotted ribs which receive a portion of the wire frame and a cam shaped rib which also holds a portion of the wire frame. The exhaust housing includes a sliding door having spaced air slots and a rear wall having similar spaced air slots alternately offset from those of the door. A hose assembly blower connection aperture is formed in the exhaust housing adjacent to the slotted rear wall. During vacuum operation the sliding door is positioned in front of the hose assembly blower aperture and air is exhausted from the motor-blower assembly through both sets of slots, but during blower operation the door is positioned in front of the rear wall with the solid portion of the door closing off the slots in the wall of the exhaust housing to concentrate all the exhaust air through the hose assembly blower connection aperture.

United States Patent Batson et al.

[ 51 June 13, 1972 [54] VACUUM CLEANER AND EXHAUST HOUSING [72]Inventors: William A. Batson, Pickens; Charles T.

Fromknecht, Anderson, both of SC.

[73] Assignee: The Singer Company, New York, N. Y.

[22] Filed: March 20, 1970 [21] Appl. No.: 21,334

[52] US. Cl ..55/417, 15/327 E, 55/472 [51] Int. Cl ..B0ld 46/02 [58]Field of Search ..55/467, 470-473, 55/410, 417; 15/327; 417/423 A;415/219 B, 207, 206; 98/41 [56] References Cited UNITED STATES PATENTS2,790,693 4/1957 I-losack ..312/295 3,032,955 5/1962 Burch ..55/4723,279,157 10/1966 Anderson-Sason et a]. .55/473 3,364,841 l/l968Uchiyama ...98/41 3,375,541 4/1968 Fromknecht 5/376 FOREIGN PATENTS ORAPPLICATIONS 812,886 5/1959 GreatBritain ..l5/32 alias wmgtgwsgfia wasPrimary Examiner--Bemard Nozick Attorney-Marshall J. Breen and ChesterA. Williams, Jr.

[ ABSTRACT A vacuum cleaner of the canister variety for domestic usehaving upper and lower housing sandwiching an intermediate housingtherebetween. An air inlet is formed at the front of the upper housingand an exhaust housing is secured to the rear of the lower housing. Adust bag is positioned between the upper and intermediate housing and isseparated from a motor blower assembly by an apertured partition wall. Awashable permanent secondary filter, fitted about a wire form frame, ispositioned on the dust bag side of the aperture in the partition wall bymeans of a pair of slotted ribs which receive a portion of the wireframe and a cam shaped rib which also holds a portion of the wire frame.The exhaust housing includes a sliding door having spaced air slots anda rear wall having similar spaced air slots alternately otfset fromthose of the door. A hose assembly blower connection aperture is formedin the exhaust housing adjacent to the slotted rear wall. During vacuumoperation the sliding door is positioned in front of the hose assemblyblower aperture and air is exhausted from the motorblower assemblythrough both sets of slots, but during blower operation the door ispositioned in front of the rear wall with the solid portion of the doorclosing off the slots in the wall of the exhaust housing to concentrateall the exhaust air through the hose assembly blower connectionaperture.

3 Claims, 6 Drawing Figures TATENTEQJUH 13 I972 3,668,842

SHEET 2 0F 2 INVENTORS j W||l|om A. Batson I Figs BY Charles C.Fromknecht ORNEY BACKGROUND OF THE INVENTION This invention relates tovacuum cleaners and more particularly to an improved canister type ofvacuum cleaner which can be operated either in a suction mode or ablower mode.

It is desirable to have the capability of operating a vacuum cleaner asa blower for various cleaning chores or for use with special attachmentssuch as a spray attachment. A blast of air exhausted from .the cleaneris thus a desirable feature under these particular circumstances.However, when operating the cleaner under normal conditions, it isobjectionable for the exhaust air to be concentrated in a blast for theobvious reason that since the air blast is directional it tends todisturb objects in its path and blow any dust in its path about withoutcontrol. It is, therefore, a requirement that vacuum cleaners bedesigned such that the air exhausted therefrom .when operating in thevacuum mode is a low velocity stream which is dispersed over a largearea.

Various prior art approaches to arrive at a balance between the twodiverse functional requirements of a dispersed exhaust for suctionoperation and a concentrated exhaust blast for blower operation havebeen attempted. Some prior art vacuum cleaners in an attempt to utilizethe exhaust port for both suction and blower modes have placed a flowdispersing filter type material over the port so that in the suctionmode the exhausted air is not emitted as a blast. This, however, reducesthe effectiveness of the blower mode since there is a designed inrestriction to an air blast. Other cleaners, in an attempt to utilizeseparate exhaust ports for suction and for blower operation haveincorporated complicated features such as special valves which open thenormal exhaust and close the blower exhaust during suction mode, andopen the blower exhaust and close the normal exhaust during the blowermode.

SUMMARY OF THE INVENTION This invention overcomes the deficiencies ofthe prior art vacuum cleaners by providing an exhaust diffuser housinghaving two apertured sections through which the air may exhaust duringthe suction mode, a first of said sections being closed during theblower mode so that all the air may be concentrated through the secondsection. The second section of the exhaust housing has a blower outletaperture into which the hose may be inserted and connected thereto whenoperating in the blower mode. The first section of the exhaust housinghas a plurality of lateral slots separated by solid portions. An exhaustdiffuser door having a plurality of lateral slots similar to those ofthe first section of the diffuser housing, but having the slots andsolid portions alternately ofiset therefrom, is slidable between thefirst and second sections. During the suction mode the slidable door ispositioned in front of the second section and air is exhausted throughboth sets of slots, but during the blower mode the door is positioned infront of the first section such that the solid portions thereof blockflow through the slots of the first section and the solid portions ofthe first section block flow through the slots of the door toeffectively close the first section and concentrate all the flow throughthe second section.

Accordingly, it is a primary object of the present invention to providein a vacuum cleaner a novel and improved construction for diffusing theexhaust air so that a dispersed stream of air is exhausted duringoperation of the cleaner in the suction mode and a concentrated blast ofair is exhausted for use as a blower.

Another object of this invention is to provide in a vacuum cleaner anovel and improved arrangement for converting from the suction to theblower mode.

A further object of this invention is the provision v in a vacuumcleaner of means for closing a portion of the exhaust diffuser toconcentrate the flow of air through another portion thereof for bloweroperation.

A still further object of this invention is the provision in a vacuumcleaner of an exhaust diffuser housing having two apertured sectionsthrough which air may exhaust during the suction mode and having a doorwhich, positioned in front of a first of said sections during saidsuction mode, allows air to flow through both sections, but which,positioned in front of the second section during the blower mode, closesoff the flow of air through the second section and forces all theexhaust air through the first section.

BRIEF DESCRIPTION OF THE DRAWINGS The particular features and advantagesof the invention, as well as other objects, will become apparent fromthe following description taken in connection with the accompanyingdrawings, in which:

FIG. 1 is a vertical sectional view substantially along the longitudinalcenter line of a vacuum cleaner embodying the present invention;

FIG. 2 is a fragmentary cross sectional view taken substantially alongthe line 2-2 of FIG. 1;

FIG. 3 is an exploded perspective view of the rear portion of the vacuumcleaner of FIG. 1 showing the exhaust diffuser housing and exhaustdiffuser door disassembled from the lower housing;

FIG. 4 is a fragmentary rear elevational view of the cleaner shown inFIG. 1 with the exhaust diffuser door positioned for operation of thecleaner in the suction mode;

FIG. 5 is a fragmentary rear elevational view of the lower portion ofthe cleaner of FIG. 1 with the exhaust diffuser door positioned foroperation of the cleaner in the blower mode; and

FIG. 6 is a cross sectional view taken substantially along 6- 6 of FIG.5.

DESCRIPTION OF PREFERRED EMBODIMENT Referring now to the accompanyingdrawings wherein like reference numerals denote similar parts throughoutthe several views, there is disclosed a canister vacuum cleanercomprising a frame having an upper housing 21, a lower housing 23, and abulkhead or intermediate housing 25 trapped by the upper and lowerhousings in sandwich-like relationship therebetween. The three housingsare fitted together at their periphery by conventional means comprisinga series of tongue and groove connections generally designated 27. Tosecure the upper housing 21 to the bulkhead 25 there are provided on theupper housing four downwardly extending integrally molded cylindricalbosses 28 (only two of which are illustrated) which register with foursimilar upwardly extending threaded bosses 29 on the bulkhead (only twoof which are illustrated). A screw 31 passes through each boss 27 and isthreadedly received within each boss 29. A threaded stud 33 fixed tocaster 35 of a front wheel assembly 37 passes through the lower housing23 at the front thereof and is threadedly received by a nut 39 bearingon the upper face of the bulkhead to secure the lower housing to thebulkhead at the front thereof. At the rear of the cleaner a pair offixed axis wheel assemblies 41 are each secured to the lower housing 23by a pair of screws 43 and 45. Each screw 43 registers with and passesin succession through a wheel bracket 47 of the assembly 4 l, a hole 49formed in the rear of the lower housing and a boss (not shown) formed inthe bulkhead, and is threadedly received in a lug (not shown) formed ina substantially V- shaped support bracket 51 secured to the upperhousing 21 by a pair of screws 53 (only one of which is illustrated)that pass through holes in the upper housing and thread into a plasticmolded tab 55. It is thus evident that the lower housing is secured tothe bulkhead by the elements that secure the wheel assemblies to thecleaner. The wheel assemblies 37 and 41 include wheels 57 each of whichcomprise a molded plastic 55 facilitate storage of the cleaner in anendwise position and allow the cleaner to be stood upon its rear endwhen cleaning areas such as steps. A seal 59 provides sealing betweenthe upper housing and the bulkhead at their outer periphery, while aconventional bumper 61 surrounds the complete cleaner to provideadditional sealing, as well as the usual protection against damagingfurniture.

The bulkhead is formed at the rear thereof with a pair of molded pockets63 and 65 within which are respectively mounted a motor blower assembly67 and an electric cord reel assembly (not shown), both of which may beof any suitable standard construction. The air moving or motor blowerassembly 67 preferably comprises a two stage fan unit 69 and a coaxialdriving motor unit 71, the motor being cooled by the high airflowcreated by the fans. Sufi'ice it to say that in the present preferredembodiment the airflow enters an inlet opening (not shown) in the front(top) of the fan unit casing and is exhausted at the motor end through acylindrically shaped motor blower guard 73 that is formed with exhaustapertures (only some of which are illustrated) in its cylindrical walland is secured to the motor frame by screws (not shown). A flat circularmounting plate 75 having a large central opening is secured by screws 77to a flange on the motor blower with a resilient seal 79 trappedtherebetween so that a portion of the seal is pressed against the motorblower flange. The pocket 63 is shaped to accept the assembled motorblower 67, mounting plate 75 and seal 79 which are then attached to aflange 80 on the pocket with a series of screws (not shown) that forcethe remaining unexposed areas of the seal into proper engagement withthe flange 80. The mounting of the motor blower in this manner effects aminimization of vibration when the unit is in operation. A conventionalpush-push switch (not shown) is mounted at the front of the cleaner toactivate and deactivate the motor blower.

A vacuum compartment, within which is located a porous filter bag 81, isformed by the walls of the bulkhead 25, the upper housing 21 and aplastic molded filter bag access door 83 which fitted over a recessedflanged opening 85 in the upper housing. Looped about each screw 31 andsecured thereby to the upper housing is one end of a wire formed spring87 having a single coil. The other end of each spring 87 is bent to forman axle, each of which fit within a hole 89 formed in a pair of tabs 91(only one of which is illustrated) extending downwardly from the rear ofdoor 83 to hingedly mount the same relative to the upper housing. At thefront of the door 83 is secured a spring bracket cam latch 93 which maybe camed under a lip on the front flange of the opening 85 to lock thedoor in the closed position. A seal 95 secured, such as by glue, aboutthe periphery of the opening 85 on the upper housing, ensures asubstantially sealed relation between the door and the housing when thedoor is shut and the latch is engaged.

Formed in the front wall of the upper housing is a central opening 97within which is inserted an intake connector 99 having a flange portion101 and a cylindrical extension 102. The connector 99 is secured in theupper housing by means of its front flanged portion 101 and an annularretaining ring 103 which together lock the connector axially to theupper housing. The connector, furthermore, includes outwardly extendinglugs (not shown) which register in notches (not shown) in the upperhousing opening to prevent rotational movement about the connector axis.A hose 105 fitted with a coupling 107 having an adaptor 109 at its otherend is connected into a frontal opening 111 of the connector 99. Theadaptor 109 includes a pair of lugs 113 (only one of which is shown)equally spaced about the periphery thereof which register with asimilarly shaped pair of notches formed in the frontal opening 111 andthe cylindrical extension 102, and which lock the hose in the inlet whenthe adaptor is given a slight clockwise twist. The disposable filter bag81 includes a cardboard mounting collar which slips onto the cylindricalextension 102 of the connector 99 and is held thereon by friction sothat the dust and dirt in the inlet airstream passing through the hoseremains in the bag as the air is drawn through the vacuum or filter bagcompartment by the motor blower assembly.

Mounted in the filter bag or vacuum compartment of the cleaner in frontof a pair of openings 117 formed in a partition wall 119 which separatesthe vacuum compartment from the motor blower compartment is a washable,permanent, secondary filter 121. This filter comprises a continuousstrip of open pore plastic foam folded into the shape of a loop orpocket and provides additional cleaning of the air after it has beendrawn through the filter bag 81 and also serves as a protective backupfilter should the filter bag rupture. The filter is formed by heatwelding or stapling the ends of a strip of resilient plastic foammaterial to form a continuous loop, pocket or receptacle. The filter isthen slipped over and about a substantially U-shaped spring metal wireform frame 123 having its central leg 125 substantially of the samelength as one half the length of the entire strip of filter material soas to hold the filter form substantially taut. The two upstanding legs127 and 129 of the frame 123 abut with the inner surface of the filterand act to support the filter and aid the central leg in holding thefilter form substantially taut. At the free end of each leg 127 and 129,the frame is bent to form a respective axle portion 131 and 132, each ofwhich sets in a slot 135 (only one is illustrated) formed in arespective upwardly extending rib 137 and 139 molded in the bulkhead 25.Extending downwardly from the upper housing 21 above the filter insubstantially the same plane as the ribs 137 and 139 of the bulkhead, isan integrally molded camming tooth 141. The filter is inserted into thecleaner by placing the axles 131 and 133 in their respective slots inthe ribs 137 and 139 and then pivoted upwardly until the leg 125 snapsunder the tooth 141 and is locked thereby between the tooth 141 and thewall 119 with the filter in a sealed relation with the wall 119 so thatthe airflow in the vacuum compartment must flow therethrough. To removethe filter 121 for cleaning or washing, the leg 125 is released fromtooth 141, the axles 131 and 133 are removed from their respectiveslots, and the filter strip is removed from the wire frame.

It should now be clear that during the suction mode of operation dirtladen air enters the cleaner through the hose 105 and passes through thebag 81 and thence through the filter 121 into the inlet ofthe fan and isexhausted at the motor end of the motor blower unit through the blowerguard 73. The exhaust air then passes through outlet apertures 143formed in the rear of the lower housing 23 and is exhausted therefromthrough an exhaust diffuser housing 145.

The housing 145 includes a pair of open slotted lugs 147 and 149 whichare trapped in position beneath the lower housing by the screws 45 whichaid in securing the wheel brackets to the lower housing. A screw 151,which passes through the housing 145 and is threadedly received in thebottom of housing 23, secures the exhaust diffuser housing in itstrapped position so that the exhaust housing and the lower housingtogether act as a conduit to conduct air from the outlets 143 to theexterior of the cleaner. The housing 145 comprises a floor 153, a rearwall extending upwardly from the floor and received within a slot 156 inthe lower housing to aid in positioning the housing 145, and a pair ofside walls 157 and 159 also extending upwardly from the floor 153 andwhich snuggly fit, when the housing is secured in position, againstrespective shoulders 161 and 163 molded on the lower housing 23. At oneend of the exhaust housing within the wall 155 is molded a recessedpocket 165 which receives an adaptor (not shown) for storing theelectric cord plug (not shown). The remainder of the housing 145comprises two apertured sections or ports formed in the rear wall 155. Afirst of these sections has an opening 167 including a pair of opposednotches 169 and 171 the opening being of the same configuration as thefrontal opening 11 1 formed in the inlet connector 99. The configurationof the opening 167 is such as to receive the hose adaptor 109 duringblower operation as will presently be described. The second sectionincludes a plurality of horizontally disposed slots 173 formed betweensimilarly disposed portions in the rear wall 155.

Formed on the floor 153 of the exhaust housing 145 are three shortupstanding ribs 175, 177 and 179 which are vertically disposed in thesame plane as two short downwardly extending ribs 181 and 183 formed onthe lower housing 23. Trapped between the ribs 175, 177, 179, 181 and183, and the rear wall 155 when the housing 145 is secured in place, isan exhaust diffuser door 185. The door 185 is slidable along the rearwall 155 in upper and lower tracks respectively formed by the ribs 181,183 and the rear wall 155, and the ribs 175, 177, 179 and the wall 155.A molded tab 187 on the door 185 acts as a finger gripping surface formoving the door between the first apertured section to the secondapertured section formed in the rear wall 155. The wall 157 and a rib188 formed as part of the cord storing pocket 165 act as stops for thedoor in its lateral travel. The door 185 includes a plurality ofhorizontally disposed slots 189 formed between solid portion of the doorand which are similar to slots 173 formed in wall 155, but the slots andsolid portions of the door 185 are alternatively staggered or offsetfrom the slots and solid portions of the wall such that, as shown inFIGS. 5 and 6, when the door is positioned in front of this section ofthe exhaust housing, the solid portions between the slots of the doorclose off the slots in the exhaust housing and the solid portionsbetween the slots of the exhaust housing close off the slots in the doorthus causing all the air from the fans to exhaust out the aperture 167.When the door is positioned as just described, all the air isconcentrated through hole 167 and the cleaner is in the blower mode. Thehose adaptor 109 may then be inserted into the opening 167 and lockedtherein by a slight clockwise twist. When suction mode operation isdesired the door 185 is slid from in front of the second section to infront of the hole 167 in the first section after the hose has beenremoved and reset in the inlet 99. The exhaust air may now pass throughboth apertured sections of the housing 145, i.e., through the hole 167and out the slots 189, and through the slots 173. By flowing throughboth sets of slots 173 and 189 during the suction mode, the exhaust airis properly dispersed.

It should be noted that although this invention has been illustratedwith the slots in the door 185 and the housing 145 being horizontallydisposed, any arrangement of apertures which would result in solidportions of each element blocking off flow through the apertures duringblower mode fall within the inventive concept of the invention. All suchmodifications which do not depart from the spirit of the invention areintended to be within the scope of the appended claims.

We claim:

1. In a vacuum cleaner of the canister type comprising a vacuum cleanerhousing having a filter compartment, a porous filter bag mounted in saidfilter compartment, an air moving unit compartment communicating withsaid filter compartment, means defining an air inlet in said housingcommunicating with said filter bag, means defining an air outlet in saidhousing communicating with said air moving unit compartment, and an airmoving unit mounted in said air moving unit compartment for drawing dirtladen air through said inlet and discharging filtered air through saidoutlet, the improvement comprising: an exhaust housing mounted to thevacuum cleaner housing in communication with said outlet for receivingsubstantially all the air discharged therethrough, said exhaust housingincluding a wall having two exhaust ports, a first of said portscomprising a single large aperture, the second port comprising aplurality of slots separated by solid portions of said wall and injuxtaposition with said single aperture, a plate having a plurality ofslots of substantially the configuration of the slots of said secondport and separated by solid portions of said plate, means defining aslideway downstream of said ports for slidably mounting said plate onsaid exhaust housing adjacent said wall, said plate being positioned insaid slideway and selectively slidable between a first positionsuperposed over said first port and a second position superposed oversaid second port, said slots and solid portions of said plate beingoffset relative to the slots and solid portions of said second port suchthat when said plate is positioned in the second position the solidportions of the plate mask the slots of said second port and the SOllClportions of said wall mask the slots of said plate.

2. In a vacuum cleaner of the canister type comprising a vacuum cleanerhousing having a filter compartment, a porous filter bag mounted in saidfilter compartment, an air moving unit compartment communicating withsaid filter compartment, means defining an air inlet in said housingcommunicating with said filter bag, means defining an air outlet in saidhousing communicating with said air moving unit compartment, and an airmoving unit mounted in said air moving unit compartment for drawing dirtladen air through said inlet and discharging filtered air through saidoutlet, the improvement comprising: an exhaust housing mounted to thevacuum cleaner housing in communication with said outlet for receivingsubstantially all the air discharged therethrough, said exhaust housingincluding a rear wall having two exhaust ports, a floor abutting saidwall, and a pair of side walls each abutting said floor and said rearwall, said floor, side walls and rear wall being disposed in abuttingrelationship to said vacuum cleaner housing and secured thereto to forma conduit for said air from said' outlet, a first of said portscomprising a single large aperture, the second port comprising aplurality of slots separated by solid portions of said wall and injuxtaposition with said single aperture, a plate having a plurality ofslots of substantially the configuration of the slots of said secondport and separated by solid portions of said plate, means defining aslideway downstream of said ports for slidably mounting said plate onsaid exhaust housing adjacent said wall, said plate being positioned insaid slideway and selectively slidable between a first positionsuperposed over said first port and a second position superposed oversaid second port, said slots and solid portions of said plate beingoffset relative to the slots and solids portions of said second portsuch that when said plate is positioned in the second position the solidportions of the plate mask the slots of said second port and the solidportions of said wall mask the slots of said plate.

3. In a vacuum cleaner as recited in claim 2 wherein said slidewaydefining means comprises at least a first rib formed on said floor andat least a second rib formed on said vacuum cleaner housing above saidwall, each of said ribs disposed in a plane substantially parallel tosaid wall.

1. In a vacuum cleaner of the canister type comprising a vacuum cleanerhousing having a filter compartment, a porous filter bag mounted in saidfilter compartment, an air moving unit compartment communicating withsaid filter compartment, means defining an air inlet in said housingcommunicating with said filter bag, means defining an air outlet in saidhousing communicating with said air moving unit compartment, and an airmoving unit mounted in said air moving unit compartment for drawing dirtladen air through said inlet and discharging filtered air through saidoutlet, the improvement comprising: an exhaust housing mounted to thevacuum cleaner housing in communication with said outlet for receivingsubstantially all the air discharged therethrough, said exhaust housingincluding a wall having two exhaust ports, a first of said portscomprising a single large aperture, the second port comprising aplurality of slots separated by solid portions of said wall and injuxtaposition with said single aperture, a plate having a plurality ofslots of substantially the configuration of the slots of said secondport and separated by solid portions of said plate, means defining aslideway downstream of said ports for slidably mounting said plate onsaid exhaust housing adjacent said wall, said plate being positioned insaid slideway and selectively slidable between a first positionsuperposed over said first port and a second position superposed oversaid second port, said slots and solid portions of said plate beingoffset relative to the slots and solid portions of said second port suchthat when said plate is positioned in the second position the solidportions of the plate mask the slots of said second port and the solidportions of said wall mask the slots of said plate.
 2. In a vacuumcleaner of the canister type comprising a vacuum cleaner housing havinga filter compartment, a porous filter bag mounted in said filtercompartment, an air moving unit compartment communicating with saidfilter compartment, means defining an air inlet in said housingcommunicating with said filter bag, means defining an air outlet in saidhousing communicating with said air moving unit compartment, and an airmoving unit mounted in said air moving unit compartment for drawing dirtladen air through said inlet and discharging filtered air through saidoutlet, the improvement comprising: an exhaust housing mounted to thevacuum cleaner housing in communication with said outlet for receivingsubstantially all the air discharged therethrough, said exhaust housingincludiNg a rear wall having two exhaust ports, a floor abutting saidwall, and a pair of side walls each abutting said floor and said rearwall, said floor, side walls and rear wall being disposed in abuttingrelationship to said vacuum cleaner housing and secured thereto to forma conduit for said air from said outlet, a first of said portscomprising a single large aperture, the second port comprising aplurality of slots separated by solid portions of said wall and injuxtaposition with said single aperture, a plate having a plurality ofslots of substantially the configuration of the slots of said secondport and separated by solid portions of said plate, means defining aslideway downstream of said ports for slidably mounting said plate onsaid exhaust housing adjacent said wall, said plate being positioned insaid slideway and selectively slidable between a first positionsuperposed over said first port and a second position superposed oversaid second port, said slots and solid portions of said plate beingoffset relative to the slots and solids portions of said second portsuch that when said plate is positioned in the second position the solidportions of the plate mask the slots of said second port and the solidportions of said wall mask the slots of said plate.
 3. In a vacuumcleaner as recited in claim 2 wherein said slideway defining meanscomprises at least a first rib formed on said floor and at least asecond rib formed on said vacuum cleaner housing above said wall, eachof said ribs disposed in a plane substantially parallel to said wall.